This is actually the norm now in todays cars. However if you feel you need to do the service, you can try and do it. There is a fill hole, drain hole, and an overflow tube hole. Personally I would never try this myself as underfilling or overfilling can be bad for the transmission. It is a bit of a process, kind of typical such as level surface, use the correct fluid, fill pan til it starts to trickle out the overflow tube, plug overflow hole , fill transmission, circulate fluid, get fluid to certain temperature, check fluid level, add more fluid if necessary.
To be honest, the only time we've ever done a transmission fill on an IS was when a customer doing his own oil change drained the transmission instead.
Good luck.